@function min($value1, $value2) {
  @if $value1 > $value2 {
    @return $value2;
  } @else if $value2 > $value1 {
    @return $value1;
  }
  @return $value1;
}

@function max($value1, $value2) {
  @if $value1 > $value2 {
    @return $value1;
  } @else if $value2 > $value1 {
    @return $value2;
  }
  @return $value1;
}

@function top($box) {
  @return parsebox($box, 1);
}

@function right($box) {
  @return parsebox($box, 2);
}

@function bottom($box) {
  @return parsebox($box, 3);
}

@function left($box) {
  @return parsebox($box, 4);
}

@function vertical($box) {
  @return top($box) + bottom($box);
}

@function horizontal($box) {
  @return left($box) + right($box);
}

@function boxmax($box) {
  @return max(max(top($box), right($box)), max(bottom($box), left($box)));
}

@function boxmin($box) {
  @return min(min(top($box), right($box)), min(bottom($box), left($box)));
}